This invention relates to vehicle accessory units such as snowplows and the like and, more particularly, to hydraulic power systems adapted to operate such accessory units.
Hydraulic systems for controlling, for example, the operative position of vehicle mounted snowplow blades are well known. These systems generally allow for varying the vertical position of the plow blade and, when in a plowing mode, the angular relationship of the plow blade relative to the path travel of the vehicle. An example of such a system is found in U.S. Pat. No. 3,307,275, issued to E.A. Simi and assigned to the assignee of this application.
Ease of installation and removal of the plow blade, its support and positioning elements, have become major considerations in recent years, along with the usual movement to simplify and improve such units. This is particularly true in connection with snowplows intended for use with relatively small vehicles such as Jeep vehicles and pickup trucks. Movement in this direction is a result of a recognition that the need for plow assemblies is seasonal and safe storage of the assemblies when not in use, either during or out of season, can extend the life of the components. Therefore, in addition to the usual movement to continually simplify the construction, there is a developing recognized need to provide for removal of the assembly from the vehicle.
This invention recognizes that those objectives, simplicity and ease of installation and removal, can be furthered by making the controls electrical. In the past, mechanical manipulation systems, such as wire extensions commonly referred to as push-pull cables, were used to activate the hydraulic power unit and to sequence the valves controlling movement to various blade orientations. A prior U.S. Pat. No. 3,706,144, issued to Marc L. Miceli discloses an electrical, solenoid operated hydraulic system embodied in a snowplow assembly of the type to which this invention relates.